KNOW YOUR BUGS
contents. They camouflage themselves by placing
their dead prey on spines on their back. Adult green
lacewings (15mm) are not predatory, feeding on
honeydew and nectar. Brown lacewings, both adults
(6 to 10mm) and larvae (5mm) are both predatory.
Pests attacked: a wide range, including moth larvae and eggs,
aphids, thrips and mites
Carabid beetles
There are several
species of carabid
beetles that feed
mostly on ground-
dwelling pests.
Larvae (10 to 25mm)
and adults (5 to
25mm) are predatory
and have prominent
mouthparts (mandibles) that protrude forward. When
disturbed the adults can emit an unpleasant odour.
Pests attacked: a wide range including true wireworms, false
wireworms, moth larvae and slugs
Hover flies
Larvae (10mm) are
effective predators of
aphids, spearing their
prey with specialised
mouth hooks, often
holding them upright,
and sucking out
the body contents.
Pupae are stuck to
the plant, teardrop
shaped and green or brown in colour. Adults
(4 to 10mm) feed on pollen and honeydew,
fly swiftly and can hover in flight.
Pests attacked: aphids
Damsel bugs
Similar in appearance, damsel bug adults (12mm)
and nymphs (smaller and without wings), are
both predatory and hold their prey with their
slightly enlarged forelegs and use their piercing
mouthparts to suck out insect body contents.
Pests attacked: include moth larvae and eggs of Helicoverpa
and diamondback moth, aphids, leafhoppers, mirids and mites
Caterpillar parasites
There are many beneficial species that parasitise
caterpillar larvae or eggs. Trichogramma
wasps (adult 0.5mm) have been used
to control caterpillar pests in a range of
horticultural and field crops. The adult
female lays eggs inside the moth eggs
and the developing wasp larvae feed
inside the egg case. The parasitised egg
turns black and the moth larva fails to
hatch and emerge. Instead, a parasitic
wasp emerges from each moth egg.
Pests attacked: Helicoverpa, diamondback moth,
lightbrown apple moth, loopers and many more
GRDC Research Codes RSS00003, CSE00046
More information: Dr Paul Umina, research and extension officer,
CESAR, 03 8344 2522, pumina@unimelb.edu.au
or curling of the leaf, a characteristic
trait from which their name derives.
Wheat curl mites are eriophyoid
mites, of which there are several
thousand identified species worldwide.
Most of these species are host-specific,
only feeding on one species of plant.
Wheat curl mites are an exception, with
extensive sampling and testing showing
that they feed on many grasses. Alternate
hosts identified in Australia by CESAR
include barley grass, great brome, annual
ryegrass, cocksfoot, black oats, prairie
grass, hairy panic, soft brome, wild
oats, winter grass and rat's tail fescue.
Wheat curl mites are reliant on their
host plant not just for food, but also for
the high humidity provided by protected
parts of the plant or within the rolled leaves
wheat curl mite create. In cooler conditions,
mites can survive for up to two weeks
away from hosts. However, they die within
a few hours if exposed to low humidity
and moderate to high temperatures.
Overseas pesticides have not been
found to be useful in controlling these
mites. Therefore at this stage, controlling
host plants -- the 'green bridge' -- is likely
to be one of the most practical methods of
reducing the build-up of wheat curl mite
numbers and the risk of WSMV. Spraying
roadside verge and grassy weeds within
paddocks over the summer months is
recommended in areas at risk of WSMV.
A commercial diagnostic seed test
has been developed for WSMV and is
available from AgWest Plant Labs, and
research into the effect of sowing seed
infected with WSMV on the spread of
the virus and yield losses is ongoing. □
GRDC Research Code UM00029
More information: Professor Ary Hoffmann,
research scientist, CESAR, 03 8344 2282,
ary@unimelb.edu.au
INTEGRATED PEST MANAGEMENT GROUND COVER 5
CARABID BEETLE
HOVER FLY
DAMSEL BUG
TRICHOGRAMMA WASP
Wheat curl mite